We consider the steady Navier-Stokes equations in a 2-dimensional unbounded multiply connected domain Ω under the general outflow condition. Let T be a 2-dimensional straight channel R × (−1, 1). We suppose that Ω ∩ {x1 < 0} is bounded and that Ω ∩ {x1 > −1} = T ∩ {x1 > −1}. Let V be a Poiseuille flow in T and µ the flux of V . We look for a solution which tends to V as x1 → ∞. Assuming that the domain and the boundary data are symmetric with respect to the x1-axis, and that the axis intersects every component of the boundary, we have shown the existence of solutions if the flux is small (Morimoto-Fujita [8]). Some improvement will be reported in this note. We also show certain regularity and asymptotic properties of the solutions.
During parasitological surveys of freshwater fish from the Miranda River, Brazil, 199 Pygocentrus nattereri kner (Characidae) were caught. Two pentastomid families, Subtriquetridae Fain, 1961, represented by its single genus Subtriquetra Sambon, 1922, and Sebekidae Sambon, 1922, represented by three genera, were present. Free-living larvae of Subtriquetra subtriquetra (Diesing, 1835) were collected from the swim bladder. Encysted larvae of Alofia Giglioli, 1922 were found in the abdominal cavity, chambers of the heart, musculature, on the surface of the gonads and swim bladder. Some Alofia larvae were moving freely in the swim bladder. Larvae of Sebekia Sambon, 1922 were encysted in the musculature. Some larvae of Leiperia Sambon, 1922 were found encysted in the musculature and on the surface of the pyloric caeca, whereas others occurred free in the abdominal cavity. In some of the latter, the head was buried deep in the wall of the intestine, stomach or ovaries, whereas the rest of their body remained free. Infective pentastomid larvae were present throughout the year with an overall prevalence of 77%. Both prevalence and intensity were higher in members of the Sebekidae than in Su. subtriquetra, possibly due to the latter's mode of transmission and its high pathogenicity. No sex-related, statistically significant differences (p > 0.05) in prevalence or abundance were found. Fish weight and length had significant but weak positive correlations (r ≤ 0.27) with the abundance of pentastomid larvae, possibly reflecting an increased likelihood of prior exposure in older fish. Parasite abundance had no significant effect on host body condition (p ≥ 0.69). A higher prevalence and monthly mean abundance of pentastomids were seen in the dry season and might be due to increased host densities as habitats dry up. Pygocentrus nattereri represents a new intermediate host record for the genera Alofia, Leiperia and Subtriquetra.
Low temperature significantly influences chloroplast development and chlorophyll (Chl) biosynthesis, so effect of coldness on Chl content and Chl fluorescence characteristics was investigated in C. bungeana (Chorispora bungeana Fisch. & C.A. Mey). The levels of transcript and protein of an enzymatic step during Chl biosynthesis in response to chilling (4°C) and freezing (-4°C) were also examined in this work. Significant reduction in total Chl content was observed, but the reduction was much less at 4°C than that at -4°C. Moreover, the maximal quantum efficiency of photosystem II (PSII) photochemistry, indicated by Fv/Fm, decreased in the first 12 h, but then started to increase and reached higher levels than the control at 24 h and 48 h at 4°C, but decreased continuously at -4°C. Whereas quantum yield of PSII (ΦPSII) showed no significant difference between the chilling-stressed and the control seedlings, at -4°C, ΦPSII was markedly reduced with the prolonged treatment. In general, there were no significant responses of photochemical quenching (qP) and non-photochemical quenching (NPQ) to cold treatment. Meanwhile, the full-length cDNA of NADPH:protochlorophyllide oxidoreductase (POR, EC 1.3.1.33) was isolated and termed CbPORB (GenBank Accession No. FJ390503). Its transcript and protein content only slightly declined at 4°C, but dramatically reduced at -4°C with the time. These results strongly suggest that CbPORB possesses certain resistant characteristics and is a major player in Chl biosynthesis process involved in plant growth and development of C. bungeana under cold environmental conditions. and Y. H. Li ... [et al.].